The invention relates to an adjustable fastening device composed of at least one sleeve nut having an aperture with a first internal thread and a through-bore following the first internal thread along a longitudinal axis (LA) of the adjustable fastening device and to a method for producing a prefabricated subassembly comprising at least one first component made of a flat material from a metal or a plastic, and an adjustable fastening device comprising at least one sleeve nut having an aperture with a first internal thread and a through-bore following the first internal thread along the longitudinal axis (LA) of the adjustable fastening device, and comprising a drum screw with an external thread and a tensioning screw lead-through.
Adjustable fastening devices for fastening at least one component made from flat material to another component, preferably a holding component, at a specified distance from one another are in principle known.
The distance between the component and the holding component is to be settable or adjustable during mounting via such a fastening device. For example, the component is a shaped part which is made by stamping, pressing and/or joining processes, namely preferably in the form of a prefabricated subassembly, and which is provided for receiving the housing wall of a household appliance.
Such adjustable fastening device are normally composed of a sleeve nut which, for accommodating a drum screw, has a cylindrical aperture with a first internal thread running concentrically to the longitudinal axis of the sleeve nut. The drum screw has an external thread which engages in the first internal thread of the sleeve nut. The sleeve nut is non-rotatably fastened with its lower free edge on the top side of the component by welding, namely in such a manner that the sleeve nut encloses a joining opening in the component and that, furthermore, the drum screw therefore can be screwed in or unscrewed from the sleeve nut through the joining opening from the bottom side of the component. The sleeve nut further has a through-bore which is situated opposite the welding edge and has a second internal thread into which a tensioning screw fed through a central tensioning screw lead-through of the drum screw can be screwed by means of its external thread.
For mounting the component on the holding component, first, the drum screw is screwed from the bottom side of the plate-like component into the sleeve nut, namely thus far that the drum screw protrudes downwards and with a predetermined distance beyond the bottom side of the plate-like component. Subsequently, the tensioning screw is first fed through a bore of the holding component and through the tensioning screw lead-through of the drum screw and screwed into the second internal thread of the sleeve nut. In doing so, the flatly formed face side of the drum screw engages on the holding component and due to the resulting friction forces and an appropriate orientation of the thread, co-rotating of the drum screw when tightening the tensioning screw is prevented. The holding component thus is clamped between the screw head of the tensioning screw and the face side of the drum screw and as a result of this, the bottom side of the plate-like component and the holding component has the distance between them that is set via the drum screw. However, it is a disadvantage that welding the sleeve nut to the plate-shaped component is required, which represents an additional time-consuming and cost-intensive work step within the production of prefabricated subassemblies. Also, the drum can be inserted into the sleeve nut only after the welding process, i.e., when mounting the prefabricated subassembly in the course of the series production, there is the disadvantage that the drum screw needs to be supplied and mounted individually.